The OpenStint Loop Preamplifier Board is an optional front-end module, designed for the OpenStint Laptimer System. It provides signal conditioning and amplification for the parallel-wire "antenna", ensuring clean, stable, and maximized signal transfer to the timing receiver.
- Fully compatible with the OpenStint timing receiver interface. Operated from the bias-tee available on HackRF One and RTLSDR.
- Output is matched to 50 Ohm.
- +12 dB gain low-noise amplifier
- Fits Hammond's 1590L-style aluminium cases
- Power pin available for 1S batteries (remove
L6orFB2in this case, or add DC-block capacitor before the SDR). - Open hardware design – schematics and PCB available under permissive license
- Directly manufacturable at JLCPCB (LCSC part codes provided).
The following measurements were made at the VNA_IN port (after the balun).
POWER GAIN
INPUT MATCHING
Add an optional 75 Ohm output as well, or add a separate 50 to 50+75 splitter. This hardware change should have a software counterpart, which reads both the OpenStint and MyLaps decoders, and merges the results into a single stream for laptiming applications. We could keep both open and commercial transponders to co-exists on the same track this way. Also, upgrading post-4.4 firmware won't be such a headache neither.
Automatic gain control: even a simple one could increase the dynamic range of the decoders.
Part of the OpenStint Laptimer System – open, modular, and precise RC timing.